# What is ADC & It’s Full Form Of ADC

## What does ADC mean?

An analog-to-digit converter is a circuit which converts a continuous voltage (analog), to a binary (digital), that can then be understood by a computer that could be used to perform digital computations. These ADC circuits are available as an individual.ADC ICsIncorporated into or by themselvesMicrocontroller. These are also known as ADCs.

### Why convert analog to digital?

The modern electronics of today are purely digital. Gone are the days when analog computers were still available. Digital systems are still analog, but the world we live is full of colour and not just black and blue.

For example a temperature sensor like the LM35 outputs a voltage dependent on the temperature, in the case of that specific device 10mV per degree rise in temperature. This will register as either a high or low depending on the input thresholds. It is useless if we connect it directly to a digital input.

Instead, we use an ADC for the conversion of analog voltage input into a series bits that can be connected directly to the microprocessor’s data bus and used to compute.

### What is an ADC?

An ADC’s working is best understood as a mathematical scaler. Scaling simply refers to mapping values between one range or another. An ADC can map a voltage value to binary numbers.

We need something that can convert voltage into a series logic levels, such as a register. Registers cannot accept logic levels as inputs. This means that if the signal were connected directly to a logic input, the results would not be satisfactory. Somebody needs to act as an interface between the analog input voltage and the logic.

These are some of the most important things.ADCs have several featuresWhile we go through them, we’ll also learn how they work.

1. 1.

The reference voltage is the voltage that is mapped to the highest binary value in an ADC. In a 10 bit converter, 5V is used as the reference voltage. 1111111111 (all bit one) corresponds to 5V, 0000000000 corresponds to the lowest number, and 0V corresponds to the highest number. Each binary step up is approximately 4.9mV since 1024 possible numbers are in 10 bits. This is the resolution of an ADC.

What happens if the voltage change is below 4.9mV per stage? The ADC is in a dead zone and the result will always be small. You can avoid this by using an ADC that has a higher resolution. ADCs with 24 bits resolution are possible, but conversion frequencies are very low at just a few hertz.

2. 2.

The sample speed is the number of digital to analog conversions a converter can do every second. A good ADC may have a sample speed of 300Ms/s. Megasamples per Second is a way to read this. It means a million samples every second. These prefixes are SI.

The type of converter used and the accuracy required to read the sample speed will determine the exact reading. If accuracy is not an issue, they can do a quick reading.

It is important to choose the right ADC for your application. Speed and accuracy are inherently proportional.

### Different types of ADCs

This is the simplest.Type of ADCThe fastest, as the name implies. It is composed of a number of comparators, with the non-inverting inputs connected at the signal input and inverting pins attached to a voltage divide ladder.

If the voltage is higher than one of the levels on the ladder, then all output bits below that level are set at one. This is because the voltage is greater than the threshold for bottom comparators. This problem can be avoided by feeding the outputs through a priority encoder, which converts it to binary.

Only the propagation delays of both the comparator or the priority encoder limit the speed. The accuracy is however moderate.

2. 2.

A ramp generating circuit and a binary counter are both started here at the time the conversion is being done. The binary counter is stopped when the ramp exceeds the input voltage by a comparator. The input voltage level determines the binary count.

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Although the accuracy of this converter is not certain, it provides good resolution and even spacing among binary steps. It’s also simple to use. This circuit can be built discretely even if there are no chips.

3. ADCs with Successive Approximation

These ADCs may be the most precise. These ADCs consist of a comparator and a simple flash DAC. In the beginning, the device assumes that all bits except the highest significant bit (which can be a one), are zeroes. This register sends the data to the DAC, which converts it into an analog voltage. The input is then compared to the comparator. The MSB will remain one if the input voltage exceeds the DAC voltage. The process continues until all bits are set to one or zero, or until the register value equals the input.

This ADC is the most widely used when accuracy and speed are not too important, such as in microcontrollers. SA-type ADCs are capable of conversion times as low as a few microseconds.

### Applications

1. Multimeter and Digital Oscilloscope

Analog oscilloscopes have the greatest advantage because there is very little circuitry between the input connectors and the screen. This means that you can see what’s happening in a circuit in real-time. They cannot store waveforms or make on-board measurements.

Digital oscilloscopes solve all these problems. At their core lies an extremely powerful and fast ADC that can resolve 12 bits or more. The ADC converts waveforms into a binary value which can be stored in memory and operated on.

2. 2. Microcontrollers

Almost all modern microcontrollers have a built in ADC, the most common being the Arduino based on the ATMega328P with a 10 bit resolution and the STM32 with a 12 bit resolution.

Arduino IDE has an ‘analogRead() function that allows you to read the analog voltage on one pin and return a 10 bit integer value. A range from 0 to 1023.

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3. Digital Power Supplies

These power supplies are now computer-controlled. An ADC is required to measure the voltage output.

### How to use an ADC IC

Many ADC ICs are available on the market that can be used to measure analog voltages. ADC0804 and ADC0808 are some of the most popular ADC modules. These modules are often used in conjunction with Raspberry pi or other digital circuits that lack an In-built ADC. Let’s take, for example, the ADS1115 ADC IC by Texas Instruments. It has high resolution and a modern architecture.

You can choose to have it in a QFN package or a VSSOP pack. This allows for very small size – almost no space on a PCB. We’ll be taking a look at some features of this chip below.

1. Compatibility with I2C

Anybody who has ever worked with microcontrollers will know how important the SPI/I2C bus is to communicate with peripherals. It is very simple to use this IC with an Arduino Board because extensive libraries have been created for it.

2. 2.

Modern ICs are very efficient and can operate at a wide voltage range, from 2.0V to 5.5V. Pay attention to the fine print below the 150uA current. It’s intended for continuous conversion mode.

3. Programmable Comparator

An ADS includes a comparator that can be programmed via the I2C bus. A discrete comparator IC is the best option for speedy application.

4. 4. Configurable inputs

You can choose to have four inputs, either two differential pairs (only voltage difference across the pins is considered) or four single-ended inputs.

This IC’s popularity among hobbyists is another plus. It makes it easy to find documentation and example codes.

### Drawbacks to ADCs

1. ADCs are slow. They can take up to a few nanoseconds.

2. Inadequacy of constant voltage values

3. Circuit complexity rises

## Summary

There are many other types of ADCs, such as ramp-compare and Wilkinson. However, the ones we will be focusing on here are the most common and readily available to consumers. ADCs can be found in various electronic devices, including digital recording equipment, televisions and microcontrollers. This background will help you to learn more aboutChoose the best ADC for you.